Froze rails gems

[depot.git] / vendor / rails / activesupport / lib / active_support / rescuable.rb

diff --git a/vendor/rails/activesupport/lib/active_support/rescuable.rb b/vendor/rails/activesupport/lib/active_support/rescuable.rb
new file mode 100644 (file)
index 0000000..c27c4dd
--- /dev/null
+++ b/vendor/rails/activesupport/lib/active_support/rescuable.rb
@@ -0,0 +1,108 @@
+module ActiveSupport
+  # Rescuable module adds support for easier exception handling.
+  module Rescuable
+    def self.included(base) # :nodoc:
+      base.class_inheritable_accessor :rescue_handlers
+      base.rescue_handlers = []
+
+      base.extend(ClassMethods)
+    end
+
+    module ClassMethods
+      # Rescue exceptions raised in controller actions.
+      #
+      # <tt>rescue_from</tt> receives a series of exception classes or class
+      # names, and a trailing <tt>:with</tt> option with the name of a method
+      # or a Proc object to be called to handle them. Alternatively a block can
+      # be given.
+      #
+      # Handlers that take one argument will be called with the exception, so
+      # that the exception can be inspected when dealing with it.
+      #
+      # Handlers are inherited. They are searched from right to left, from
+      # bottom to top, and up the hierarchy. The handler of the first class for
+      # which <tt>exception.is_a?(klass)</tt> holds true is the one invoked, if
+      # any.
+      #
+      #   class ApplicationController < ActionController::Base
+      #     rescue_from User::NotAuthorized, :with => :deny_access # self defined exception
+      #     rescue_from ActiveRecord::RecordInvalid, :with => :show_errors
+      #
+      #     rescue_from 'MyAppError::Base' do |exception|
+      #       render :xml => exception, :status => 500
+      #     end
+      #
+      #     protected
+      #       def deny_access
+      #         ...
+      #       end
+      #
+      #       def show_errors(exception)
+      #         exception.record.new_record? ? ...
+      #       end
+      #   end
+      def rescue_from(*klasses, &block)
+        options = klasses.extract_options!
+
+        unless options.has_key?(:with)
+          if block_given?
+            options[:with] = block
+          else
+            raise ArgumentError, "Need a handler. Supply an options hash that has a :with key as the last argument."
+          end
+        end
+
+        klasses.each do |klass|
+          key = if klass.is_a?(Class) && klass <= Exception
+            klass.name
+          elsif klass.is_a?(String)
+            klass
+          else
+            raise ArgumentError, "#{klass} is neither an Exception nor a String"
+          end
+
+          # put the new handler at the end because the list is read in reverse
+          rescue_handlers << [key, options[:with]]
+        end
+      end
+    end
+
+    # Tries to rescue the exception by looking up and calling a registered handler.
+    def rescue_with_handler(exception)
+      if handler = handler_for_rescue(exception)
+        handler.arity != 0 ? handler.call(exception) : handler.call
+        true # don't rely on the return value of the handler
+      end
+    end
+
+    def handler_for_rescue(exception)
+      # We go from right to left because pairs are pushed onto rescue_handlers
+      # as rescue_from declarations are found.
+      _, rescuer = Array(rescue_handlers).reverse.detect do |klass_name, handler|
+        # The purpose of allowing strings in rescue_from is to support the
+        # declaration of handler associations for exception classes whose
+        # definition is yet unknown.
+        #
+        # Since this loop needs the constants it would be inconsistent to
+        # assume they should exist at this point. An early raised exception
+        # could trigger some other handler and the array could include
+        # precisely a string whose corresponding constant has not yet been
+        # seen. This is why we are tolerant to unknown constants.
+        #
+        # Note that this tolerance only matters if the exception was given as
+        # a string, otherwise a NameError will be raised by the interpreter
+        # itself when rescue_from CONSTANT is executed.
+        klass = self.class.const_get(klass_name) rescue nil
+        klass ||= klass_name.constantize rescue nil
+        exception.is_a?(klass) if klass
+      end
+
+      case rescuer
+      when Symbol
+        method(rescuer)
+      when Proc
+        rescuer.bind(self)
+      end
+    end
+  end
+end